Musical instrument



June 2, 1942. 1 A. MAAS MUSICAL INSTRUMENT Filed April l2, 1940 2 Sheets-Sheei. l

AMPLIFIER 16 INVENTOR. LoL/i5 A Mcms maa JL ATTORNEY.

June 2, 1942. L. A. MAAS 2,284,911

MUSICAL INSTRUMENT Filed April l2, 1940 2 Sheets-Sheet 2 83 65 V54 58 a/ mln-1x7 fa -57 'L' S6/g AMPL f-/ER 88 MPL FIER III INVENTOR.

ATTORNEY.

Patented June 2, 1942 uNITEDIsTATEs Application April l2,

5 Claims.

My invention relates to a musical .instrument "andmore particularly to means for electrically `v:amplifying musical vibrations ot a vibrating e. g., converting the vibrations of -`"c'lil'rr'ies into corresponding electrical impulses and amplifying such impulses.

y"Iliemusical instrument comprises hammers at,de1iver blows against chimes, and an lm- 4'.,po'ta'nt object of the invention is to provide "j cans in such a musical instrument to substantially eliminate audible effect by the instrument, of the percussion blows of the hammer.

l Another object is to provide a pick-up device at'will avoid materially dampening the vibra- ,Y onspf the chime.

A"further object is to provide resilient, vibratpolarized lbodies of diierent shapes than M chimes by lwhich such bodies are vibrated, rom which bodies electrical impulses are corresponding to the vibrations of such still further object is to be able to vary at ,wi1l, within a prescribed range, the capacity ben'the chime and the polarized body, to vobthe,V desired amount of signalenergy from eachfcliime.` y

'ljhei'nvention also comprises novel details of i construction and novel combinations .and arents of parts, which will more fully apver, the drawings merely show and the Ioldescription merely describes an kembodiof the present invention, which is given by ay,.oi illustration or example only.`

"' he drawings, like reference characters des- Lire 1 is an elevation of a tubular chime 'agrammatic view of a striking means cirnisifanlenlarged, broken face nnther :modified construction.

EigUlfc-ffazis a side elevation o'fa bar -dieatigua oithe presentinventlon.

lEigure/iifjisgacplanview, looking in the direction of the arrows 6-6 of Figure 5. y

. liguregisaproken, transverse sectional view,

View of chime en p l1 1ofriglure5y.

in underneath sectional kView taken on the'l'ine B-l of Figure 5.

PATENT OFFICE 2,284,911 Musical. INSTRUMENT Lann a. Mau,

Glendale, Calif. 1940, serial Nn. :29,260

` Figure 9 is a broken, transverse section, taken on the line 1 1 of Figure 5, but showing a modied construction.

Figure l is an end view of a magnetic pickup device, with an amplifying circuit shown in diagrammatic form.

Figure l1 is a broken, side elevation looking in the direction of the arrow il of Figure 10.

Referring more in detail to the'drawings, the reference number I5 generally designates a tu.- bular chime which may be provided with a non.n metallic or other striking head I6 and suspended by a cord I1, all as more particularly shown and described in United States Letters Patent No. 1,813,171, issued July 7, 1931, on an invention by Joseph W. Klein.

A percussion device for the chime comprises a solenoid I8 whose core I9 strikes the chime when the solenoid is energized by a source of electrical energy. I A manual key 2l operates a switch 22 that controls the circuit 23 for the y solenoid.

Mounted on the body of the chime I5 is a polarizing plate 24, with a dielectric I 4, such as of varnished linen, disposed between the plate and the chime, An end of a wire 25 is held against the plate 24 by another dielectric strip 26, which rin turn is held in place by a spring wire 21. Screws 28 and 29 on the chime l5 hold the spring wire 21 resillently 'against the 'dielectric 24 and thereby yieldingly hold the end of the Wire 25 andthe plate 24 in place with respect to the chime.

A similar spring wire 30 resiliently maintains the opposite end of the plate 24 in place. A dielectric 26 is arranged between the wire 30 and the kplate 24. Screws 32 and 33 maintain the wire 30 in its resilient clamping position with l respect .tothe plate 24. y '.By unscrewing the screws 28, 29, 32 and 33,

the plate 24is permitted to vibrate at greater `amplitude and thus produces a correspondingly Lstronger' impulse in the wire 25; By tightening these screws, the amplitude of the vibrations of theplate 24` is reduced, thus producing a correl. spondingly weaker electrical impulse in the wire 25. ,"A `condenser microphone circuit includes the wire 25 in which a polarizing voltage is obtained from an electrical source 34, which source is connecte'drwith the wire 25 through a resistance 35. `Wire 36, that connects the source 34 with the resistance 35 is tapped by a wire 31 that contains v f ure 9.

l source i4 are connectedby a wire 44 to the chime those skilled in the vA conventional dynamic speaker, connected with the amplifier, is indicated at 4l.

The'plate 24.is. preferably ofa different sectional shape'than the contour of the tubular chime l5. If the plate 24is curved (which is not essential), itis preferably in an are of greater or smaller radius than thev radius of the"tubular chime. Figure 2 shows the plate 24 curved and of a greater radius than the tubular chime i5, thus providing loose edges 4,5 that vibrate when the plate 24 is set in vibration by the vibration of the chime.

Figure 3 shows a plate 41 that is curved and is of a smaller radius than the tubular chime I5,

devices hereinbefore described are electrostatic pick-ups. However, a magnetic pick-up may also be used, where the chime is of magnetic material. For a magnetic pick-up a horseshoe magnet l5 is disposed with itsv poles in close proximity to the bar chime 50. A bracket 5I supports magnet I5 in substantially rigid relationship tothe frame 50. A coil 5i. around the magnet has itsopposite ends connected by wires I2v and!! to anamplier S4. A conventional dynamic speaker 951s connected y-to the amplifier 04. up 'In the operation of each electrostatic pick-up form of the invention shown and described, a re- 'silient,v vibrating member carries a polarized plate which in turn isresilient and vibrated by the vibrating, carrying member. In one form of lthe invention, a magnetic pick-up is employed.

whereby the edges 48 of the plate 41 contact the dielectric l4 and the center portion of the plate 41 vis bowed outwardly from the chime. The endv of the wire 25 may be knotted, as shown at 49.1to prevent it being drawn outwardly from between the dielectric 25 and the plate 24 or 41.`

. Inthe forml shown in Figure 4, a single di-A agonally arranged spring wire 5l is fastened to v the chime i5 by screws 5| and 52.' A diagonally arranged dielectric 5l is disposed between Athe resilient wire 5l and the plate 24.

Figure 5 shows a' modified construction of a chime,to wit. two floating bar chimes 54 and 55 of the same pitch. Nodal points of the bar chime 54`hav e apertures 5 5 in which are hooked the ends. of coil spring 51. It is. believed clear without further 'illustration that the bar chimes y may be supported on leather, rubber or felt pads, or supported by string at nodal points of the chimes. The opposite ends of the springs 51 are looped about posts 54. A base 55 supports the posts 5I.v The tubular chimes also have nodal pointsv and vibrating portions.

-plate carried 'by the chime.

With either the electrostatic Vpick-up or the` magnetic pick-up, the sound.- of the percussion blow Ymay beeliminated by employing two associated chimes of the sarnepi'll. striking one of the chimes, inducing vibrations in the second chime by close association of the twochimes, and picking up the vibrations ofthesecond chime. The vibrating chlme'and 'the vlbratingpiate are electrodes in'the-circuit.

The polarized plate is preferably ofa'dlffere'nt Y radius thanthe tubular chime, if such a` c hime `is used, andthe plate is preferably curved if the chime'is a flat,-barchime. This difference in radius or shape provides a wider variance'betweenk the vibration oi' the chime and of the -The clamp for vmaintaining the plate lin position' on the 'chime is preferably one that 'does -not extend around the chime and.: thereby re- 'strict vibration thereof.

r-It is to be understood that` the present drawings show only a single unitof a musicalr instru- The adjacent bar chime $4 has apertures 5I" in which' are hooked springs'52, which in turn are looped about postsl 5l. A spring wire 63 is fastened' at one end by a-bolt 54 on a nodal line of the bar chime 5B. The opposite end of the spring wire 43 `'yieldingly holds the end of a wire 14 against a dielectric between a curved plate 66 and the chime GII. A dielectric 61 is arranged between the wire 5I and the plate The plate may be oppositely curved, as shown at I5I in Fig- A bolt 15 and nut 14 fasten a grounded wire 11 to a nodal point on the bar chime 54.

Percussion. mechanism for the initial bar chime 54 comprises a solenoidA 59 having a core 10 that strikes the bar 54 `when the solenoid is actuated by electrical currentfrom'a source 1l. A key 12 controls a switch 1I for the circuit 14 of the solenoid. y y An amplifier 1l is connnected with the wire 1l by means vof `a wire Il that contains a blocking condenser 4I. The amplifier 19 is grounded at l2. A resistance 42 is connected with the wire 14 and to a source I4 ofv electrical current by vmeans of a wire I5. A grounded by-pass condenser 55 taps the wire 45 between the resistance 8l and the source I4. The said source is grounded at 41. A conventional dynamic speaker It is connected with the amplifier 1I. The pick-up ment. A plurality of such units, havingchimes of different pitch l(pitched. to thev ordinary musical scale) are arranged together with a keyboard p composed'ofa plurality of keys 2i or 12.

By 4anoperator manipulating lsuch keys, the

- vchimes I5 or" 54 are struck. The vibration ofthe chime i5 induces vibration of the plate 24, 41, 65'

or 4.8, whose vibrations are picked up by the wire 25, ampli-fled ,and-discharged as sounds by the loudspeaker 45. Vibrations of the chime 54 invducetlie chime 5D to vibrate. y"ll'he plate'SB or the magnet ljpick upthe vibrations-of vthe bar 4chime, subsequent towhch the means-described amplify' same and reproduce them at the loud, speaker Il or 95. f' While I have illustrated and described what I now regard as thepreferred embodiment of my lill invention, the constructiohis. of course, vsubject to modifications without departing from the spirit and' scopev of my invention. Ltherefore, do not wish to restrict' myself tov the particular form of construction illustrated anddescribed but desire to avail myself of all Imodifications `whichmay fall within the scope of the appended gl aims.

Having thus described .my invention,A what l claim and desire to secure by Letters Patent is:

1.V A chime, comprising a chime member forming one part of a condenser, a plate insulated from said chime member,`and insulated spring members supporting said plate on' the chime member.v the said lplate having a different conrespect to one another to provide a varying space therebetween.

4. The invention as set forth in claim 3, Wherein one of the vibrating members is curved in a degree forming a variation in its contour with respect to the contour of the other member.

5. The invention as set forth in claim 3, with means insulated from one of said members for adjustably, yieldingly connecting the members.

LOUIS A. MAAS. 

